CN109690181B - Sheet for covering optical semiconductor element - Google Patents

Abstract

The present invention provides a sheet for covering an optical semiconductor element, the sheet for covering an optical semiconductor element is a sheet for directly or indirectly covering an optical semiconductor element, and includes a white layer containing white particles and a white layer containing light diffusing particles in this order along the thickness direction the light diffusion layer.

Description

Sheets for covering optical semiconductor elements

technical field

The present invention relates to a sheet for covering an optical semiconductor element.

Background technique

Conventionally, as a light-emitting device capable of emitting high-energy light, a white light semiconductor device has been known. A white light semiconductor device includes, for example, a diode substrate that supplies power to the LEDs; LEDs (Light Emitting Diodes) that are mounted on the diode substrate and emit blue light; and a phosphor layer that covers the LEDs and can convert blue light into yellow light. The white light semiconductor device emits high-energy white light by color mixing of blue light and yellow light, wherein the blue light is emitted from the LED and transmitted through the phosphor layer, and the yellow light is obtained by wavelength-converting a part of the blue light in the phosphor layer.

As such an optical semiconductor light-emitting device, for example, the optical semiconductor light-emitting device of Patent Document 1 is proposed. The optical semiconductor light-emitting device of Patent Document 1 includes a semiconductor multilayer film including a light-emitting layer and a base substrate, and a phosphor film covers the side surface and the upper surface (surface opposite to the base substrate) of the optical semiconductor multilayer film form.

According to the optical semiconductor light-emitting device of Patent Document 1, the yield of the optical semiconductor light-emitting device can be improved without increasing the size of the device.

Patent Document 1: Japanese Patent Laid-Open No. 2005-252222

However, in the optical semiconductor light-emitting device of Patent Document 1, the light emitted from the semiconductor multilayer film and the phosphor film is not uniform due to different emission angles. Specifically, the light emitted in the oblique direction is slightly yellowish than the light emitted in the frontal direction (upper side). As a result, color unevenness is caused by different angles of emission. In particular, when the optical semiconductor device is viewed in the straight upward direction, a yellow ring (yellow ring) is observed in white light.

In addition, in general, in the phosphor layer, a yellow phosphor is often used as the phosphor. Therefore, when not emitting light, the optical semiconductor light-emitting device itself appears yellow, which causes a problem that the appearance of the optical semiconductor light-emitting device deteriorates in design.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a sheet for covering an optical semiconductor element with which an optical semiconductor element having color uniformity in different angular directions and good appearance when not emitting light can be easily produced.

The optical semiconductor element-covering sheet of the first aspect of the present invention is used for directly or indirectly covering an optical semiconductor element, and has a white layer containing white particles and a light-diffusing layer containing light-diffusing particles in this order in the thickness direction.

The sheet for covering an optical semiconductor element according to the second aspect of the present invention is the sheet for covering an optical semiconductor element according to the first aspect, wherein the luminance L* in the thickness direction of the sheet for covering an optical semiconductor element is 51.2 or more and 67.7 or less.

In the optical semiconductor element covering sheet of the third aspect of the present invention, in the second aspect, the luminance L* in the thickness direction of the optical semiconductor element covering sheet is 55.7 or more and 66.6 or less.

In the optical semiconductor element covering sheet according to the fourth aspect of the present invention, in any one of the first to third aspects, the half-value angle of the light-diffusion layer is 20° or more and 120° or less.

In the optical semiconductor element covering sheet according to the fifth aspect of the present invention, in the fourth aspect, the half-value angle of the light-diffusion layer is 40° or more and 120° or less.

In the optical semiconductor element covering sheet according to the sixth aspect of the present invention, in any one of the first to fifth aspects, the thickness of the white layer is 30 μm or more and 200 μm or less.

In the optical semiconductor element covering sheet according to the seventh aspect of the present invention, in any one of the first to sixth aspects, the thickness of the light-diffusion layer is 30 μm or more and 600 μm or less.

In the optical semiconductor element covering sheet of the eighth aspect of the present invention, in any one of the first to seventh aspects, the light-diffusion layer contains a B-stage resin.

According to the ninth aspect of the present invention, the sheet for covering an optical semiconductor element is based on the eighth aspect, wherein the light diffusing layer is measured by dynamic viscoelasticity under the conditions of a frequency of 1 Hz and a heating rate of 20° C./min. The curve of the relationship between the energy modulus G' and the temperature T has a minimum value in which the temperature T is in the range of 40°C or higher and 200°C or lower, and the shear storage modulus in the minimum value is The amount G' is in the range of 1000Pa or more and 90000Pa or less.

According to the optical semiconductor element covering sheet of the present invention, by covering the optical semiconductor element with the optical semiconductor element covering sheet, the white layer containing white particles and the light diffusing layer containing light diffusing particles can be arranged in the optical semiconductor element. Therefore, it is possible to easily obtain a covered optical semiconductor element having color uniformity in different angular directions and an attractive appearance when not emitting light.

Description of drawings

FIG. 1 shows a cross-sectional view of an embodiment of the cover sheet of the present invention;

2A to 2F are flowcharts of a method of manufacturing a three-layered cover element, FIG. 2A shows a step of preparing a phosphor layer-covered element assembly, FIG. 2B shows a step of setting a cover sheet, and FIG. 2C shows a cover sheet with respect to the phosphor. Figure 2D shows the step of peeling off the peeling sheet, Figure 2E shows the step of cutting off the three-layer covering element assembly, and Figure 2F shows the step of installing the three-layer covering element;

3A to 3B show a three-layer covering element fabricated by the manufacturing method of FIGS. 2A to 2F , FIG. 3A shows a top view, and FIG. 3B shows a cross-sectional view of A-A in FIG. 3A ;

FIGS. 4A to 4F are flowcharts showing a modification of the method for manufacturing a three-layer cover element (an embodiment in which only the light-diffusing layer is arranged on the upper surface of the phosphor layer cover element), and FIG. 4A shows the preparation of the phosphor layer cover element assembly. 4B shows the step of arranging the side part of the light diffusing layer, FIG. 4C shows the step of setting the cover sheet, FIG. 4D shows the step of pressing the cover sheet with respect to the phosphor layer covering element assembly, and FIG. 4E shows the peeling The step of peeling off the sheet, FIG. 4F shows the step of cutting off the three-layer covering element assembly;

FIGS. 5A to 5B show a modification of the three-layer cover element (embodiment having the edge portion of the light diffusion layer and the edge portion of the white layer) produced by the manufacturing method of FIGS. 4A to 4F , FIG. 5A is a plan view, and FIG. 5B is a view A cross-sectional view of A-A of 5A;

6 shows a schematic diagram of a device for measuring the half-value angle of a light-diffusion layer according to an embodiment;

Fig. 7 shows the relationship between the shear storage modulus G' and the temperature T of the phosphor layers of the examples.

tag description

1: Cover sheet

2: white layer

3: Light diffusing layer

6: Optical semiconductor components

Detailed ways

In FIG. 1, the upper and lower directions of the paper are the up-down direction (the first direction, the thickness direction), the upper side of the paper is the upper side (the first direction side, the thickness direction side), and the lower side of the paper is the lower side (the first direction and the thickness direction). The other side in one direction, the other side in the thickness direction). The left-right direction on the page is the left-right direction (an example of the second direction perpendicular to the first direction, and the vertical direction relative to the up-down direction), the left side of the page is the left side (the second direction side), and the right side of the page is the right side (the other side in the second direction). The paper thickness direction is the front-rear direction (an example of the third direction perpendicular to the first and second directions, and the vertical direction relative to the up-down direction), the front side of the paper surface is the front side (the third direction side), and the paper surface The inner side is the rear side (the other side in the third direction). Specifically, it is based on the directional arrows in the respective drawings.

<One Embodiment>

An embodiment of the sheet for covering an optical semiconductor element (hereinafter simply referred to as a covering sheet) of the present invention will be described with reference to FIG. 1 .

1. Cover sheet

The cover sheet 1 is a sheet for directly or indirectly covering the optical semiconductor element, and has a shape like a plate (sheet) extending in the plane direction (direction perpendicular to the thickness direction, front-rear direction, and left-right direction). The cover sheet 1 has a white layer 2 and a light diffusion layer 3 in this order in the thickness direction. The cover sheet 1 consists only of the white layer 2 and the light diffusion layer 3 .

In addition, the cover sheet 1 is not the three-layer cover element 5 (refer to FIGS. 2E and 3B ) to be described later, and is also not the optical semiconductor device 10 (refer to FIG. 2F ). That is, the cover sheet 1 is a part of the three-layer cover member 5 and the optical semiconductor device 10 , that is, a member for manufacturing the three-layer cover member 5 and the optical semiconductor device 10 . Therefore, the cover sheet 1 does not include the optical semiconductor element 6 and the substrate 15 on which the optical semiconductor element 6 is mounted (refer to FIG. 2F ), and the cover sheet 1 itself can be distributed as a component and can be used industrially.

2. White layer

The white layer 2 has a shape like a plate (flake) extending in the plane direction. The white layer 2 in the three-layer cover element 5 is a white layer that appears white in appearance when not emitting light.

The white layer 2 contains white particles. Specifically, the white layer 2 is composed of a white composition containing white particles and a first resin.

As the white particles, white inorganic particles and white organic particles are exemplified. From the viewpoint of heat dissipation and durability, white inorganic particles are preferred.

Examples of materials constituting the white inorganic particles include oxides such as titanium oxide, zinc oxide, zirconium oxide, and aluminum oxide, carbonates such as lead white (basic lead carbonate) and calcium carbonate, and clay minerals such as kaolin. From the viewpoints of brightness and whiteness, oxides are preferred, and titanium oxide is more preferred.

The average particle diameter of the white particles is, for example, 0.1 μm or more, preferably 0.2 μm or more, and, for example, 2.0 μm or less, preferably 0.5 μm or less. When the average particle diameter of the white particles is within the above range, the whiteness can be further improved.

In the present invention, the average particle diameter of particles such as white particles, light-diffusing particles, fillers, and thixotropy-imparting particles is calculated as the D50 value, and specifically, measured by a laser diffraction particle size distribution analyzer.

The content of the white particles relative to the white composition is, for example, 1.0% by mass or more, preferably 2.0% by mass or more, more preferably 2.5% by mass or more, and, for example, 9.0% by mass or less, preferably 7.0% by mass or less, and more preferably 6.0% by mass below quality.

The first resin is a resin capable of constituting a matrix in which white particles can be dispersed. As such a first resin, a thermosetting resin and a thermoplastic resin can be mentioned, and a thermosetting resin is preferable.

As the thermosetting resin, a secondary reaction curable resin and a primary reaction curable resin can be mentioned.

The two-stage reaction-curable resin has two reaction mechanisms, and can change from the A-stage to the B-stage (semi-cured) by the first-stage reaction, and then from the B-stage to the C-stage (complete curing) by the second-stage reaction. That is, the secondary reaction-curable resin is a thermosetting resin that can become a B-stage under appropriate heating conditions. The B-stage is a state in which the thermosetting resin is in a state between the liquid A-stage and the fully cured C-stage, and is a semi-solid state or a solid state in which the compressive elastic modulus is less than that of the C-stage by being slightly cured and gelled.

The primary reaction-curable resin has a reaction mechanism, and can change from A stage to C stage (complete curing) by the first stage reaction. Such a first-stage reaction curable resin includes a thermosetting resin that can stop the reaction in the middle of the first-stage reaction and can change from the A stage to the B stage, and can restart the first-stage reaction by further heating thereafter. And from B-stage to C-stage (full cure). That is, the above-mentioned thermosetting resin is a first-order reaction-curable resin that can become a B-stage. In addition, the primary reaction curable resin also includes a thermosetting resin that cannot be controlled to stop in the middle of the primary reaction, that is, cannot become a B-stage, but can change from A-stage to C-stage (complete curing) at one time. That is, the above-mentioned thermosetting resin is a first-order reaction-curable resin that cannot become a B-stage.

Preferably, as the thermosetting resin, thermosetting resins (secondary reaction-curable resins and primary reaction-curable resins) that can be B-staged are exemplified.

As a thermosetting resin which can become a B-stage, for example, silicone resin and epoxy resin are preferable, for example, silicone resin is more preferable.

In addition, as the silicone resin that can become the B-stage, there are mentioned silicone resins having both thermoplasticity and thermosetting properties (thermoplastic/thermosetting silicone resins), and silicone resins having thermosetting properties without thermoplasticity (non-thermoplastic/thermosetting silicone resins). Thermoplastic/thermosetting silicone resins are preferred.

The thermoplastic/thermosetting silicone resin is temporarily plasticized (or liquefied) by heating in the B-stage, and then cured by further heating (C-stage). Specifically, examples of the primary reaction curable resin include phenyl-based silicone resin compositions described in Japanese Patent Laid-Open Nos. 2016-037562 and 2016-119454, for example. Examples of the secondary reaction curable resin include the first to sixth thermoplastic/thermosetting silicone resin compositions (for example, double-terminal amino group-containing silicone Resin composition and octasilsesquioxane cage-containing composition) and the like. For example, a phenyl-based silicone resin composition is preferable.

The phenyl-based silicone resin composition has a phenyl group under the main skeleton of a siloxane bond. As the phenyl-based silicone resin composition, for example, an addition reaction curable silicone resin composition is preferable. Specifically, for example, an addition reaction-curable silicone resin composition including an alkenyl group-containing polysiloxane, a hydrosilyl group-containing polysiloxane, and a hydrosilylation are exemplified, for example, and the like. A catalyst, and one of the alkenyl group-containing polysiloxane and the hydrosilyl group-containing polysiloxane has a phenyl group. The phenyl-based silicone resin composition softens in the further heating described above (representing a minimum point), but is harder than ordinary thermoplastic/thermosetting silicone resins.

Examples of the non-thermoplastic/thermosetting silicone resin secondary reaction curable resin include the first to eighth condensation/addition reaction curable silicone resins described in Japanese Patent Laid-Open Nos. 2010-265436 and 2013-187227, for example. composition.

Moreover, as a thermosetting resin which does not employ|adopt a B-stage, an addition reaction curable silicone resin composition is mentioned. As an addition reaction curable silicone resin composition that does not use the B-stage, commercially available products (eg, trade names: KER-2500, KER-6110, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: LR-7665, manufactured by Asahi Kasei WACKER Corporation) can be used. ).

Such an addition-reaction-curable silicone resin composition that does not use the B-stage has substantially only methyl groups under the main skeleton serving as a siloxane bond, for example. In addition, this silicone resin composition is a methyl-based silicone resin composition.

The refractive index of the first resin is, for example, 1.30 or more and 1.75 or less. In particular, the refractive index of the phenyl-based silicone resin composition of the resin at the C stage is, for example, 1.45 or more, preferably 1.50 or more, more preferably 1.55 or more, and, for example, 1.75 or less, preferably 1.65 or less. In addition, the refractive index of the methyl-based silicone resin composition of the resin is, for example, 1.30 or more, for example, 1.35 or more, and, for example, 1.50 or less, in the C stage. In the present invention, the refractive index can be measured using an Abbe's refractometer.

The content of the first resin relative to the white composition is, for example, 10 mass % or more, preferably 20 mass % or more, and, for example, 99 mass % or less, preferably 98 mass % or less, and more preferably 90 mass % or less.

The white composition may have particles such as thixotropy imparting particles and fillers in addition to the above-mentioned components.

The thixotropy-imparting particles are thixotropic agents that impart thixotropy (thixotropy) or increase thixotropy to white compositions. Thixotropy is a property in which the viscosity gradually decreases if the shear stress is continued, and the viscosity gradually increases if it is at rest. In this way, the white particles can be uniformly dispersed in the white composition (and further in the white layer 2 ), and a uniform appearance (white) without color unevenness can be exhibited during non-luminescence.

From the viewpoint of dispersibility, the thixotropy-imparting particles are preferably nano-silica such as fumed silica or the like.

Examples of fumed silica include dimethyldichlorosilane, hydrophobic fumed silica whose surface is hydrophobized by a surface treatment agent such as silicone oil, and hydrophilic fumed silica that has not undergone surface treatment. A sort of.

The average particle diameter of nano-silica (particularly fumed silica) is, for example, 1 nm or more, preferably 5 nm or more, and, for example, 200 nm or less, preferably 50 nm or less. In addition, the specific surface area (BET method) of nano-silica (particularly fumed silica) is, for example, 50 m ² /g or more, preferably 200 m ² /g or more, and, for example, 500 m ² /g or less.

When the white composition contains thixotropy-imparting particles, the content of the thixotropy-imparting particle white composition is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and, for example, 10% by mass or less, preferably 3% by mass the following.

The filler is transparent particles and has a small difference in refractive index with the first resin. Specifically, the absolute value of the refractive index difference with the first resin is, for example, 0.03 or less, preferably 0.01 or less. In this way, the transparency of the white layer 2 can be ensured, and the rigidity of the white layer 2 can be improved.

As the filler, the same as the filler described later in the light-diffusing composition, for example, glass particles are preferable.

When the white composition contains a filler, the content of the filler relative to the white composition is, for example, 5% by mass or more, preferably 10% by mass or more, and, for example, 80% by mass or less, preferably 70% by mass or less .

The thickness T1 of the white layer 2 is, for example, 30 μm or more, preferably 50 μm or more, and, for example, 200 μm or less, or preferably 180 μm or less.

When the thickness of the white layer 2 is equal to or greater than the above-mentioned lower limit, the color of the phosphor layer 7 can be blocked more effectively, and the appearance when not emitting light can be further rendered white. On the other hand, if the thickness of the white layer 2 is below the above-mentioned upper limit, the reflection back to the optical semiconductor element 6 by the white layer 2 can be sufficiently prevented, and the brightness can be maintained.

3. Light diffusion layer

The light-diffusion layer 3 has a shape like a plate (sheet) extending in the plane direction. The light-diffusion layer 3 is a diffusion layer, and diffuses the light emitted from the optical semiconductor element 6 (see FIG. 3B ).

The thickness of the light diffusion layer 3 is 100 μm, and the light transmittance when irradiated with light having a wavelength of 450 nm is, for example, more than 30%, preferably 40% or more, and, for example, 80% or less, preferably 70% or less.

The light-diffusion layer 3 contains light-diffusion particles. Specifically, the light-diffusing layer 3 is formed of, for example, a light-diffusing composition containing light-diffusing particles and a second resin.

The light-diffusing particles are transparent particles that diffuse light, and examples thereof include particles having a large difference in refractive index with the second resin.

Specifically, light-diffusing inorganic particles, light-diffusing organic particles, and the like are exemplified.

Examples of the light-diffusing inorganic particles include silica particles and composite inorganic oxide particles.

The composite inorganic oxide particles are preferably glass particles, and specifically, contain silica or silica and boron oxide as main components, and contain alumina, calcium oxide, zinc oxide, strontium oxide, and magnesium oxide as sub-components , zirconia, barium oxide and antimony oxide, etc. The content of the main component in the composite inorganic oxide particles relative to the composite inorganic oxide particles is, for example, 40 mass % or more, preferably 50 mass % or more, and, for example, 90 mass % or less, preferably 80 mass % or less. The content of the auxiliary components is the remainder of the content ratio of the above-mentioned main components.

Examples of the light-diffusing organic particles include acrylic resin particles, styrene-based resins, acrylic-styrene resin particles, silicone-based resin particles, polycarbonate-based resin particles, benzoguanamine-based resin particles, and polyolefin-based resins. Particles, polyester-based resin particles, polyamide-based resin particles, polyimide-based resin particles, and the like. Preferred are, for example, acrylic resin and silicon-based resin particles, more preferably, for example, silicon-based resin particles.

From the viewpoint of light diffusivity and durability, the light diffusing particles are preferably, for example, light diffusing inorganic particles, more preferably, for example, silica particles and glass particles, and still more preferably, for example, silica particles.

The refractive index of the light-diffusing particles can be appropriately set according to the refractive index of the second resin, and is, for example, 1.40 or more, preferably 1.45 or more, and, for example, 1.60 or less, preferably 1.55 or less.

The absolute value of the refractive index difference between the light diffusing particles and the second resin is, for example, 0.04 or more, preferably 0.05 or more, more preferably 0.10 or more, and, for example, 0.20 or less, preferably 0.18 or less. When the refractive index difference is less than the said lower limit, sufficient light diffusivity may not be exhibited. On the other hand, if the difference in refractive index is higher than the above upper limit, the optical properties such as brightness will be degraded due to excessive light diffusion.

The average particle diameter of the light-diffusing particles is, for example, 1.0 μm or more, preferably 2.0 μm or more, and, for example, 10 μm or less, preferably 5.0 μm or less.

The content of the light-diffusing particles relative to the light-diffusing composition is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably 30% by mass or more, and, for example, 60% by mass or less, preferably 50% by mass or less, More preferably, it is 40 mass % or less. In addition, the content ratio of the main component of the light-diffusing particles to the light-diffusing composition is, for example, 40 mass % or more, preferably 50 mass % or more, and, for example, 90 mass % or less, preferably 80 mass % or less.

The second resin is a transparent resin that can constitute a matrix in which light-diffusing particles can be dispersed. As the second resin, the same resin as that of the first resin is exemplified. Curable resins are preferred, thermosetting resins capable of becoming a B-stage are more preferred, thermoplastic/thermosetting silicone resins are still more preferred, and phenyl silicone resin compositions are particularly preferred.

The content of the second resin relative to the light-diffusing composition is, for example, 10 mass % or more, preferably 20 mass % or more, and, for example, 90 mass % or less, preferably 80 mass % or less, and more preferably 60 mass % or less.

The light-diffusing composition may contain particles such as thixotropy-imparting particles and fillers in addition to the above-mentioned components.

The thixotropy-imparting particles are, for example, the same particles as the above-mentioned thixotropy-imparting particles in the white composition. Fumed silica is preferred.

When the light-diffusing composition contains thixotropy-imparting particles, the content of the thixotropy-imparting particles with respect to the light-diffusing composition is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and, for example, 10% by mass or less, Preferably it is 3 mass % or less.

The filler is transparent particles and has a small difference in refractive index with the second resin. Specifically, the absolute value of the difference in refractive index with the second resin is, for example, 0.03 or less, or preferably 0.01 or less. Thereby, the transparency of the light-diffusion layer 3 can be ensured, and the rigidity of the light-diffusion layer 3 can be improved.

The refractive index of the filler is appropriately set according to the refractive index of the second resin, and is, for example, 1.40 or more, preferably 1.45 or more, and, for example, 1.60 or less, preferably 1.55 or less.

Examples of such fillers include inorganic particles and organic particles. Inorganic particles are preferred.

Examples of the inorganic particles include particles of the same material as the light-diffusing particles, and composite inorganic oxide particles (glass particles, etc.) are preferred.

Examples of the organic particles include particles of the same material as the light-diffusing organic particles.

The average particle diameter of the filler is, for example, 1.0 μm or more, preferably 5.0 μm or more, and, for example, 100 μm or less, preferably 50 μm or less.

When a filler is contained, the content rate of the filler with respect to the light-diffusing composition is, for example, 5 mass % or more, preferably 10 mass % or more, and, for example, 50 mass % or less, preferably 30 mass % or less.

In addition, in the particles used in the present invention, even if the material is the same, it is possible to appropriately distinguish whether it is a light-diffusing particle or a filler according to the difference in refractive index of the resin.

The thickness T2 of the light diffusing layer 3 is, for example, 30 μm or more, preferably 50 μm or more, more preferably 100 μm or more, and, for example, 600 μm or less, preferably 500 μm or less, and more preferably 200 μm or less.

If the thickness of the light-diffusion layer 3 is more than the said lower limit, since light can be diffused reliably, the color uniformity of different angle directions can be improved. On the other hand, when the thickness of the white layer 2 is below the above-mentioned upper limit, the decrease in optical properties can be reduced, and a more beautiful appearance can be obtained when the light is not emitted.

The half-value angle α of the light diffusing layer 3 is, for example, 20° or more, preferably 40° or more, more preferably 80° or more, further preferably 100° or more, and, for example, 180° or less, preferably 150° or less, More preferably, it is 120 degrees or less. When the half-value angle is equal to or greater than the above lower limit, light can be effectively diffused, so that the color uniformity in different angular directions can be improved. The method of measuring the half-value angle is described in detail in the examples.

4. Manufacturing method of cover sheet

The cover sheet 1 can be manufactured by the following steps: a white layer forming step of forming the white layer 2 on the surface of the release sheet 4 (lower surface in FIG. 1 ); and forming a light diffusion layer on the surface of the white layer 2 (lower surface in FIG. 1 ) 3 steps of forming the light diffusing layer.

(white layer formation step)

In order to form the white layer 2, for example, a white resin composition (paint) is first prepared. Specifically, the white particles and the first resin can be prepared by compounding and mixing particles other than the white particles (filler, thixotropy-imparting particles, etc.) if necessary.

Next, the white composition is applied on the surface of the release sheet 4 and dried.

The release sheet 4 is formed of, for example, a flexible film extending in the plane direction. Examples of the release sheet 4 include polymer films such as polyethylene films and polyester films, for example, ceramic sheets, and for example, metal foils. In addition, if necessary, the contact surface of the release sheet 4, that is, the surface on which the white composition is applied, is subjected to release treatment such as fluorine treatment. The thickness of the release sheet 4 is, for example, 1 μm or more, preferably 10 μm or more, and, for example, 2000 μm or less, or preferably 1000 μm or less.

Next, when the white composition contains a thermosetting resin, the white composition is C-staged. Specifically, the A-stage white composition is heated (drying) to be C-staged.

The heating (drying) conditions are appropriately adjusted according to the type of the white composition, and the heating temperature is, for example, 100°C or higher, preferably 110°C or higher, and, for example, 150°C or lower, preferably 130°C or lower. The heating time is, for example, 5 minutes or more, preferably 10 minutes or more, and, for example, 480 minutes or less, preferably 300 minutes or less. In addition, heating can be performed multiple times at different temperatures.

In this way, the white layer 2 is formed on the surface of the release sheet 4 . Specifically, the C-stage white layer 2 is formed.

(Light-diffusion layer forming step)

In order to form the light-diffusion layer 3, for example, a light-diffusion layer composition (paint) is first prepared. Specifically, it is prepared by compounding and mixing the light-diffusing particles, the second resin, and, if necessary, particles other than the light-diffusing particles (filler, thixotropy-imparting particles, and the like).

Next, the light-diffusion layer composition is coated on the surface of the white layer 2 and dried.

Next, when the light-diffusion layer composition contains a thermosetting resin, the light-diffusion layer composition is B-staged. Specifically, the A-stage light-diffusion layer composition is heated (baking) to be B-staged.

The heating (baking) conditions are appropriately adjusted according to the type of the light-diffusion layer composition, and the heating temperature is, for example, 50°C or higher, preferably 70°C or higher, and, for example, lower than 100°C, preferably 90°C or lower. The heating time is, for example, 1 minute or more, preferably 5 minutes or more, and, for example, 30 minutes or less, preferably 20 minutes or less.

In this way, the light-diffusion layer 3 is formed (arranged) on the surface of the white layer 2 . Specifically, the B-stage light-diffusion layer 3 is formed. That is, the resin contained in the light-diffusion layer 3 is in a B stage.

As a result, the cover sheet 1 including the white layer 2 and the light-diffusion layer 3 is obtained in a state supported by the release sheet 4 .

The luminance L* in the thickness direction of the cover sheet 1 is, for example, 51.2 or more, preferably 55.7 or more, more preferably 60.0 or more, and, for example, 67.7 or less, preferably 66.6 or less, and more preferably 62.5 or less. In addition, the brightness of the cover sheet 1 is substantially the same regardless of the state (B stage or C stage) of the resin contained. The measurement of brightness is measured by an ultraviolet-visible-near-infrared spectrometer and a transmittance measurement method of an integrating sphere, which will be described in detail in the examples.

If the luminance is at least the above lower limit, the total luminous flux of the light emitted from the three-layer covering element 5 is good, and the luminance of the three-layer covering element 5 is good. On the other hand, when the luminance is equal to or less than the above upper limit, the color of the phosphor layer 7 can be blocked more effectively, and the appearance during non-light emission can be further rendered white.

The thickness of the cover sheet 1 is, for example, 50 μm or more, preferably 150 μm or more, and, for example, 1000 μm or less, preferably 500 μm or less.

5. Manufacturing method of three-layer covering element

Next, a method of covering the optical semiconductor element 6 with the cover sheet 1 will be described with reference to FIGS. 2A to 2F . Specifically, a method of manufacturing the three-layered cover element 5 by covering the cover sheet 1 on the phosphor layer cover element 8 will be described.

The manufacturing method of the three-layer covering element 5 includes, for example: a preparation step of preparing a phosphor layer covering element assembly 11; a lamination step, heat-bonding the cover sheet 1 with respect to the phosphor layer covering element assembly 11; a peeling step, The peeling sheet is peeled; and in the cutting step, the three-layer covering element aggregate 12 is cut.

(preparatory steps)

In the preparation step, as shown in FIG. 2A , the phosphor layer covering element assembly 11 is prepared.

The phosphor layer covering element assembly 11 includes a plurality of phosphor layer covering elements 8 and a temporary fixing sheet 30 for temporarily fixing the plurality of phosphor layer covering elements 8 .

The phosphor layer covering element 8 includes an optical semiconductor element 6 and a phosphor layer 7 covering the optical semiconductor element 6 .

The optical semiconductor element 6 is, for example, an LED (Light Emitting Diode Element) or an LD (Semiconductor Laser Element) that converts electrical energy into light energy. Preferably, the optical semiconductor element 6 is a blue LED emitting blue light. On the other hand, the optical semiconductor element 6 does not include a rectifier (semiconductor element) such as a transistor whose technical field is different from that of the optical semiconductor element 6 .

The optical semiconductor element 6 has a quasi-flat plate shape extending in the planar direction. In addition, the optical semiconductor element 6 has a pseudo-rectangular shape in plan view (preferably, a pseudo-square shape in plan view). The optical semiconductor element 6 includes an upper surface 21, a lower surface 22, and a side surface 23 (refer to FIG. 3B).

The upper surface 21 is a light-emitting surface that emits light upward, and has a flat shape. A phosphor layer 7 (described later) is provided on the upper surface 21 .

The lower surface 22 is a surface on which the electrodes 24 are formed, and is arranged to face the upper surface 21 with a space therebetween. The electrodes 24 are provided in plural (two), and have a shape slightly protruding toward the lower side from the lower surface 22 .

The side surface 23 is a light-emitting surface that emits light, and connects the circumferential end edge of the upper surface 21 and the circumferential end edge of the lower surface 22 . The side surface 23 includes four surfaces, a front surface 23a, a rear surface 23b, a left surface 23c, and a right surface 23d (see FIG. 3B ).

The optical semiconductor element 6 emits light toward five directions (ie, upper side, front side, rear side, left side, and right side) from at least five faces (ie, upper surface 21 and side surface 23 ).

The dimensions of the optical semiconductor element 6, specifically, the thickness (length in the vertical direction) can be appropriately set, for example, 0.1 μm or more, preferably 10 μm or more, more preferably 100 μm or more, and, for example, 2000 μm or less, preferably 1500 μm Below, it is more preferable that it is 500 micrometers or less. The length in the plane direction (left-right direction and/or front-rear direction) of the optical semiconductor element 6 is, for example, 200 μm or more, preferably 500 μm or more, and, for example, 3000 μm or less, preferably 2000 μm or less.

The phosphor layer 7 contains a phosphor and converts the wavelength of light emitted from the optical semiconductor element 6 . The phosphor layer 7 is disposed above and on the side of the optical semiconductor element 6 and covers the upper surface 21 and side surfaces 23 (front surface 23a, rear surface 23b, left surface 23c, and right surface 23d) of the optical semiconductor element 6. That is, the phosphor layer 7 is arranged above and around the optical semiconductor element 6 and completely covers the five surfaces other than the lower surface of the optical semiconductor element 6 . The phosphor layer 7 has a pseudo-rectangular shape in plan view (preferably, a square shape in plan view), and is formed so as to include the optical semiconductor element 6 when projected up and down.

Examples of the phosphor include a yellow phosphor capable of converting blue light into yellow light, and a red phosphor capable of converting blue light into red light. For example, a yellow phosphor is preferable.

Examples of the yellow phosphor include silicate phosphors such as (Ba, Sr, Ca) ₂ SiO ₄ : Eu, (Sr, Ba) ₂ SiO ₄ : Eu (barium orthosilicate (BOS)), for example, those having Y Garnets having garnet-type crystal structures such as ₃ Al ₅ O ₁₂ : Ce (YAG (Yttrium, Aluminum, Garnet): Ce), Tb ₃ Al ₃ O ₁₂ : Ce (TAG (Terbium, Aluminum, Garnet): Ce) Stone-type phosphors, for example, oxynitride phosphors such as Ca-α-SiAlON, and the like.

The vertical length L1 (thickness, see FIG. 3B ) of the phosphor layer 7 arranged above the optical semiconductor element 6 is, for example, 10 μm or more, preferably 50 μm or more, more preferably 100 μm or more, and, for example, 500 μm or less, preferably It is 400 micrometers or less, More preferably, it is 300 micrometers or less.

The temporary fixing sheet 30 includes a support base 31 and a pressure-sensitive adhesive layer 32 arranged on the support base 31 .

Examples of the support substrate 31 include polymer films such as polyethylene films and polyester films (PET, etc.), for example, ceramic sheets, and flexible sheets such as metal foils.

The pressure-sensitive adhesive layer 32 is arranged on the entire upper surface of the support base 31 . The pressure-sensitive adhesive layer 32 has a sheet shape on the upper surface of the support base 31 . The pressure-sensitive adhesive layer 32 is formed of, for example, a pressure-sensitive adhesive whose pressure-sensitive adhesive force is reduced by treatment (eg, irradiation of ultraviolet rays, heating, or the like). The thickness of the pressure-sensitive adhesive layer 32 is, for example, 1 μm or more, preferably 10 μm or more, and, for example, 1000 μm or less, preferably 500 μm or less.

In the phosphor layer-covered element assembly 11 , the plurality of phosphor layer-covered elements 8 are attached to the temporary fixing sheet so that the lower surface 22 of the phosphor layer-covered element 8 is adhered to the upper surface of the pressure-sensitive adhesive layer 32 . 30 are arranged to be spaced apart from each other. At this time, the plurality of electrodes 24 are embedded in the pressure-sensitive adhesive layer 32 .

Such a phosphor layer-covered element assembly 11 can be produced by referring to, for example, the methods described in Japanese Patent Laid-Open No. 2014-168036, Japanese Patent Laid-Open No. 2016-119454, and the like.

(pressing step)

In the lamination step, as shown in FIGS. 2B and 2C , the cover sheet 1 is thermocompression-bonded with respect to the phosphor layer covering element assembly 11 .

First, a thermocompression bonding machine 43 including a lower plate 41 and an upper plate 42 is prepared. The upper plate 42 is relatively arranged above the lower plate 41 at an interval and can be moved to the upper surface of the lower plate 41 during pressing. A heating device (not shown) is provided on the lower plate 41 and the upper plate 42, and these can be heated to a predetermined temperature.

Next, as shown in FIG. 2B , the phosphor layer covering element assembly 11 and the covering sheet 1 are set on the press 43 . Specifically, a phosphor layer is disposed on the upper surface of the lower plate 41 to cover the element assembly 11 . Moreover, the cover sheet 1 is fixed to the lower surface of the upper plate 42 so that the light-diffusion layer 3 may become the lower side.

Next, as shown in FIG. 2C , the upper plate 42 is moved downward, and the cover sheet 1 is pressed against the phosphor layer cover element assembly 11 . At this time, the lower plate 41 and the upper plate 42 are heated by the heating device.

The heating temperature is, for example, 40°C or higher, preferably 45°C or higher, and, for example, 200°C or lower, preferably 150°C or lower.

The pressing pressure is, for example, 0.01 MPa or more, preferably 0.1 MPa or more, and, for example, 10 MPa or less, preferably 5 MPa or less.

The pressing time is, for example, 1 second or more, preferably 10 seconds or more, and, for example, 30 minutes or less, preferably 10 minutes or less.

Thereby, the phosphor layer covering element 8 is buried in the light diffusing layer 3 . Specifically, the top and side surfaces of the phosphor layer covering element 8 are covered with the light diffusing layer 3 , and the exposed surface of the temporary fixing sheet 30 (the upper surface portion exposed from the phosphor layer covering element 8 ) is covered with the light diffusing layer 3 .

As a result, the three-layer cover element assembly 12 including the temporary fixing sheet 30 , the plurality of optical semiconductor elements 6 , the phosphor layer 7 , the light diffusion layer 3 and the white layer 2 is obtained in the state where the release sheet 4 is laminated.

(peeling step)

In the peeling step, as shown by the phantom line in FIG. 2D , the peeling sheet 4 is peeled off from the three-layer covering element aggregate 12 . That is, the peeling sheet 4 is peeled off from the white layer 2 .

Next, when the light-diffusion layer 3 is B-staged, the thermosetting resin is completely cured (C-staged). Specifically, for example, the three-layer covering element assembly 12 is heated with an oven or the like.

The heating temperature is, for example, 100°C or higher, preferably 120°C or higher, and, for example, 200°C or lower, preferably 160°C or lower. Further, the heating time is, for example, 10 minutes or more, preferably 30 minutes or more, and, for example, 480 minutes or less, preferably 300 minutes or less. In addition, multiple heating at different temperatures can be performed.

When a phenyl silicone resin composition is used as the resin, the content of the phenyl group of the hydrocarbon group directly bonded to the silicon atom in the C-stage product is, for example, 30 mol% or more, preferably 35 mol% or more, and, for example, 55 mol% or less, preferably 50 mol% or less. The content of phenyl groups was calculated by ²⁹ Si-NMR. For example, WO2011/125463 etc. describe the detailed calculation method of the content rate of a phenyl group.

(cutting step)

In the cutting step, as shown in FIG. 2E , the three-layer covering element assembly 12 is cut (separated into pieces).

Specifically, as shown by the dotted line in FIG. 2D , the white layer 2 and the light-diffusion layer 3 are completely cut in the thickness direction between the optical semiconductor elements 6 adjacent to each other. Thereby, the three-layer covering element assembly 12 is singulated into each phosphor layer covering element 8 . Therefore, the white layer 2 and the light-diffusion layer 3 are united in a one-to-one correspondence with one phosphor layer covering element 8 .

In order to cut the white layer 2 and the light-diffusion layer 3, for example, a cutting device using a narrow-width disc-shaped dicing saw, for example, a cutting device using a knife, for example, a cutting device such as a laser irradiation device is used.

Next, as shown by the phantom line in FIG. 2E , the temporary fixing sheet 30 is peeled off from the optical semiconductor element 6 .

Thereby, the three-layer cover element 5 including the optical semiconductor element 6 , the phosphor layer 7 , the light diffusion layer 3 and the white layer 2 is obtained.

As shown in FIGS. 3A and 3B , in the three-layer cover element 5 , the light diffusing layer 3 is arranged on the upper side and the side of the phosphor layer 7 , and covers the upper surface and the side surface of the phosphor layer 7 . That is, the light-diffusion layer 3 is arranged above and around the phosphor layer 7 , and completely covers the five surfaces other than the lower surface of the phosphor layer 7 . The phosphor layer 7 has a pseudo-rectangular shape in plan view (preferably a pseudo-square shape in plan view), and is formed to include the phosphor layer 7 when projected up and down.

The vertical length L2 (thickness) of the light diffusing layer 3 arranged on the upper side of the phosphor layer 7 is, for example, 30 μm or more, preferably 50 μm or more, more preferably 100 μm or more, and, for example, 600 μm or less, preferably 500 μm or less, More preferably, it is 200 μm or less.

The white layer 2 is arranged on the upper side of the light diffusing layer 3 and covers the upper surface of the light diffusing layer 3 . That is, the white layer 2 is arranged on the upper side of the light diffusing layer 3 and completely covers only the upper surface of the light diffusing layer 3 . The white layer 2 has a rectangular shape in plan view (preferably a pseudo-square shape in plan view), and is formed so as to match the light diffusion layer 3 when projected up and down.

The vertical length L3 (thickness) of the white layer 2 is, for example, 30 μm or more, preferably 50 μm or more, and, for example, 200 μm or less, or preferably 180 μm or less.

The three-layer cover element 5 is not the optical semiconductor device 10 (see FIG. 2F ), that is, does not include the substrate 15 included in the optical semiconductor device 10 . That is, the three-layer cover member 5 is configured such that the electrodes 24 are not yet electrically connected to the terminals (not shown) provided on the substrate 15 of the optical semiconductor device 10 . In addition, the three-layer cover member 5 is a component of the optical semiconductor device 10 , that is, a component used for manufacturing the optical semiconductor device 10 , and can be distributed separately as a component and can be used industrially.

2F , by flip-chip mounting the three-layer cover element 5 on a substrate 15 such as a diode substrate, an optical semiconductor device 10 such as a light-emitting diode device is obtained.

The substrate 15 has a shape similar to a flat plate, and specifically, is formed of a laminate in which a conductor layer is laminated as a circuit pattern on an upper surface of an insulating substrate. The insulating substrate is composed of, for example, a silicon substrate, a ceramic substrate, a plastic substrate (eg, a polyimide resin substrate) or the like. The conductor layer is formed of conductors such as gold, copper, silver, and nickel, for example. The conductor layer includes electrodes (not shown) for electrical connection with the singular optical semiconductor elements 6 . The thickness of the substrate 15 is, for example, 25 μm or more, preferably 50 μm or more, and, for example, 2000 μm or less, preferably 1000 μm or less.

<Action effect>

Since the cover sheet 1 has the white layer 2 containing the white particles and the light diffusing layer 3 containing the light diffusing particles in this order in the thickness direction, the white layer 2 containing the white particles and the light diffusing particles can be arranged in the phosphor layer cover element 8 the light diffusing layer 3.

In particular, the light-diffusion layer 3 can be arranged on the upper surface and the side of the phosphor layer covering element 8 . Therefore, the white light emitted from the phosphor layer covering element 8 can be reliably diffused in the light-diffusion layer 3, and the color unevenness in the frontal direction and the oblique direction can be reduced. That is, the color uniformity in different angular directions is good. As a result, it is possible to prevent a yellow ring or the like due to color unevenness in the white light emitted from the three-layer cover element 5 from being observed.

Furthermore, the white layer 2 can be arranged on the outermost surface of the three-layer covering element 5 . Therefore, when not emitting light (and when emitting light), the three-layer cover element 5 appears white. As a result, the appearance is beautiful.

In addition, since the cover sheet 1 can be disposed on the phosphor layer cover element 8 by thermocompression, it is possible to easily manufacture a three-layer cover element with good color uniformity in different angular directions and good appearance (whiteness) when not emitting light 5.

<Variation>

In the following modified examples, the same reference numerals are assigned to the same components as those of the embodiment in FIGS. 1 to 3B , and detailed explanations are omitted.

(1) In the manufacturing method of the three-layer cover element 5 shown in FIGS. 2A to 2F , the cover sheet 1 is placed on the phosphor layer to cover the top surface and the side surface of the phosphor layer 7 so that the light diffusion layer 3 covers On the element 8, for example, as shown in FIGS. 4A to 4F, the cover sheet 1 may be disposed on the phosphor layer covering element 8 so that the light diffusing layer 3 covers only the upper surface of the phosphor layer 7.

In the embodiment shown in FIGS. 4A to 4F , in the cover sheet 1 , it is preferable to make the light diffusion layer 3 in the B stage, and its hardness is higher than that of the B stage light diffusion used in FIGS. 2A to 2F . Layer 3 is slightly harder.

Specifically, all of the following conditions [1] to [3] are satisfied.

[1] The curve representing the relationship between the shear storage modulus G' and the temperature T obtained by measuring the dynamic viscoelasticity of the light diffusing layer 3 under the conditions of a frequency of 1 Hz and a heating rate of 20° C./min has a minimum value .

[2] The temperature T of the minimum value is in the range of 40°C or higher and 200°C or lower.

[3] The shear storage modulus G' of the minimum value is in the range of 1000Pa or more and 90000Pa or less. It is preferably 10000Pa or more, more preferably 20000Pa or more, still more preferably 30000Pa or more, and preferably 70000Pa or less.

By making the light diffusing layer 3 satisfy the above-mentioned conditions, the light diffusing layer 3 can be attached to the phosphor layer covering member 8 with good adhesion, and the thickness of the light diffusing layer 3 before and after pressing can be maintained. In addition, the thickness of the light-diffusion layer 3 attached to the phosphor layer-covering element 8 can be made uniform more reliably.

In addition, in order to manufacture the cover sheet 1 including the light-diffusion layer 3 that satisfies the above-mentioned conditions, for example, a phenyl silicone resin composition is used as the second resin, and when the light-diffusion layer 3 is B-staged, it is cured. The degree is higher than the light diffusing layer 3 of the cover sheet 1 used in the embodiment shown in FIGS. 2A-2F . That is to say, the degree of heating increases.

Specifically, the heating temperature is, for example, 70°C or higher, preferably 80°C or higher, and, for example, 150°C or lower, preferably 140°C or lower, and the heating time is, for example, over 10 minutes, preferably 12 minutes or longer, and more preferably in 15 minutes or more, and, for example, 60 minutes or less, preferably 50 minutes or less.

In addition, in the light-diffusion layer 3 of the cover sheet 1 according to the embodiment shown in FIGS. 2A to 2F , the shear storage modulus G′ of the minimum value of the above-mentioned condition [3] is, for example, less than 1000Pa, preferably 500Pa Below, and, for example, 10 Pa or more.

Next, a method of manufacturing the three-layer cover element 5 by covering the phosphor layer cover element 8 using the cover sheet 1 of the embodiment shown in FIGS. 4A to 4F will be described.

The manufacturing method of the three-layer covering element 5 includes, for example: a preparation step of preparing a phosphor layer covering the element assembly 11; a light diffusing layer disposing step, disposing the light diffusion layer side portion 13 on the phosphor layer covering the element assembly 11; step, the phosphor layer covering the element assembly 11 with the light-diffusion layer side portion 13 disposed with respect to the cover sheet 1 is thermocompressed; the peeling sheet 4 is peeled off; and the three-layer covering element assembly 12 is cut off. Cut off step.

As shown in FIG. 4A, the preparation steps are the same as those shown in FIG. 2A.

In the light-diffusion layer arrangement step, as shown in FIG. 4B , the light-diffusion layer side portion 13 is arranged on the phosphor layer covering element assembly 11 . Specifically, before the lamination step, in the phosphor layer-covered element assembly 11 , the light-diffusion layer side portion 13 is arranged between the plurality of phosphor layer-covered elements 8 .

In order to arrange the light-diffusion layer side portion 13 , for example, a light-diffusion composition is potted between the plurality of phosphor layer covering elements 8 . Next, when the light-diffusing composition contains a thermosetting resin, the light-diffusing composition is B-staged by heating or the like. Alternatively, thermocompression bonding is performed on the phosphor layer-covered element assembly 11 using a light-diffusion layer-side transfer sheet including the B-stage light-diffusion layer side portion 13 and a release sheet.

At this time, the light-diffusion layer side part 13 is arrange|positioned so that the upper surface of the formed light-diffusion layer side part 13 and the upper surface of the fluorescent substance layer 7 may lie on the same plane. If necessary, polishing processing is performed on the upper surface of the light-diffusion layer side portion 13 and/or the phosphor layer 7 .

In the lamination step, as shown in FIGS. 4C to 4D , the cover sheet 1 is thermocompression-bonded with respect to the phosphor layer covering element assembly 11 on which the light-diffusing layer side portions 13 are arranged. The conditions of thermocompression bonding are the same as the compression bonding steps shown in FIG. 2B-FIG. 2C.

Thereby, the light-diffusion layer 3 is arrange|positioned so that the upper surface of the fluorescent substance layer 7 and the light-diffusion layer side part 13 may be covered.

As a result, the three-layer cover element assembly 12 including the temporary fixing sheet 30, the plurality of optical semiconductor elements 6, the phosphor layers 7, The light diffusing layer side portion 13 , the light diffusing layer 3 and the white layer 2 . At this time, the light-diffusion layer side portion 13 of the phosphor layer covering the element assembly 11 is integrated with the light-diffusion layer 3 of the cover sheet 1 to form one light-diffusion layer.

In the peeling step, as shown by the phantom line in FIG. 4E , the peeling sheet 4 is peeled off from the phosphor layer covering element assembly 11 . That is, the peeling sheet 4 is peeled off from the white layer 2 and the light-diffusion layer side part 13 .

Next, when the light-diffusion layer 3 and/or the light-diffusion layer side part 13 are B-staged, the thermosetting resin is completely cured (C-staged). Specifically, for example, the three-layer covering element assembly 12 is heated with an oven or the like. The heating conditions were the same as those shown in Fig. 2E.

In the cutting step, as shown in FIG. 4F , the three-layer covering element assembly 12 is cut (united).

Specifically, the white layer 2 , the light-diffusing layer 3 , and the light-diffusing layer side portion 13 are completely cut in the thickness direction between the optical semiconductor elements 6 adjacent to each other, as shown by the dotted line in FIG. 4E . Thereby, the three-layer covering element assembly 12 is singulated into each phosphor layer covering element 8 .

The cutting method is the same as that of the cutting step shown in FIG. 2E.

Thereby, the three-layer cover element 5 is obtained, which includes the optical semiconductor element 6 , the phosphor layer 7 , the light diffusion layer side portion 13 , the light diffusion layer 3 , the white layer 2 , and the light diffusion layer side portion 13 .

The manufacturing method of the embodiment shown in FIGS. 4A to 4F can also achieve the same functions and effects as the manufacturing method of the embodiment shown in FIGS. 2A to 2F . In particular, in the three-layer cover element 5 obtained by the manufacturing method of the second embodiment, the thickness L2 of the light-diffusion layer 3 arranged on the upper surface of the phosphor layer 7 and the light-diffusion layer 3 of the cover sheet 1 can be adjusted to of the same thickness. Therefore, the thickness design of the light-diffusion layer 3 becomes easy.

(2) In addition, in the embodiment described in the above (1) ( FIGS. 4A to 4F ), the light-diffusion layer side portion 13 is arranged on the phosphor layer covering the element assembly 11 , but, for example, refer to FIGS. 5A to 5A . In FIG. 5B , the cover sheet 1 is thermocompression-bonded with respect to the phosphor layer covering element assembly 11 without disposing the light-diffusion layer side portion 13 .

At this time, thermocompression bonding is performed using a mold or the like so that the light-diffusion layer 3 of the cover sheet 1 is in contact with the upper surface (exposed surface) of the temporary fixing sheet 30 .

Thereby, the three-layer covering element 5 shown in FIGS. 5A-5B can be obtained.

In the three-layer covering element 5 shown in FIGS. 5A-5B , the light diffusing layer 3 includes: an upper part 51 of the light diffusing layer, which is arranged on the upper surface of the phosphor layer 7; The side of the bulk layer 7; and the light-diffusing layer edge portion 53, which protrudes from the lower end of the light-diffusing layer side portion 52 to the side. The thickness of the upper part 51 of the light diffusion layer (length in the vertical direction), the thickness of the side part 52 of the light diffusion layer (length in the front-rear direction/the length in the left and right direction), and the thickness of the edge part 53 of the light diffusion layer (length in the vertical direction) are the same as each other.

The white layer 2 includes: a white layer upper part 61 disposed on the upper surface of the light diffusing layer upper part 51; a white layer side part 62 disposed on the side of the light diffusing layer side part 52; and a white layer edge part 63 extending from The lower end of the white layer side portion 62 protrudes laterally. The thickness (vertical length) of the white layer upper portion 61 , the thickness of the white layer side portion 62 (front-rear length/left-right length), and the thickness (vertical length) of the white layer edge portion 63 are the same as each other.

The above-mentioned embodiment of manufacturing the three-layer covering element 5 shown in FIGS. 5A-5B can also achieve the same effect as the embodiment shown in FIGS. 4A-4F .

(3) In addition, in the embodiment shown in FIGS. 2A to 2F , the cover sheet 1 is indirectly covered on the optical semiconductor element 6, that is, the cover sheet 1 is covered on the phosphor layer covering element 8, for example, although Although not shown, the cover sheet 1 may directly cover the optical semiconductor element 6 .

That is, the cover sheet 1 can be arranged on the optical semiconductor element 6 that does not include the phosphor layer 7 so that the light diffusion layer 3 is in contact with the upper surface of the optical semiconductor element 6 . Also in the above-described embodiment, the same functions and effects as those of the embodiment shown in FIG. 2 can be achieved.

(4) In addition, in the embodiment shown in FIGS. 2A to 2F , the cover sheet 1 covers the phosphor layer cover element 8 , although not shown, it may cover the optical semiconductor device. That is, in the optical semiconductor device in which the optical semiconductor element 6 is mounted on the substrate 15 , the cover sheet 1 can be covered on the above-mentioned optical semiconductor element 6 . In the above-mentioned embodiments, the same functions and effects as those of the embodiments shown in FIGS. 2A to 2F can be achieved.

[Example]

Specific numerical values such as blending ratios (content ratios), physical properties, and parameters used in the following description may be replaced by the corresponding blending ratios (content ratios), physical property values, parameters, and the like described in the above-mentioned "Embodiment". The upper limit (defined as a value of "below" and "less than") or the lower limit (defined as a value of "above" and "exceeding").

<Preparation of Silicone Resin Composition>

Based on Preparation Example 1 described in the Examples of JP-A No. 2016-037562, an A-stage phenyl silicone resin composition (a first-stage reaction-curable resin capable of becoming a B-stage) was prepared.

Next, the A-staged phenyl silicone resin composition was reacted at 100° C. for 1 hour (completely cured, C-staged) to obtain a product. ²⁹ Si-NMR of the obtained product was measured, and the ratio (mol%) of the phenyl group in the hydrocarbon group directly bonded to the silicon atom was calculated, and the result was 48%.

In addition, the refractive index of the phenyl silicone resin composition at the C stage was measured with an Abbe refractometer. The result is 1.56.

<Material Used in Examples>

Titanium oxide: white particles, average particle size 0.36 μm, trade name “R706S”, manufactured by DuPont

Silica particles: light-diffusing particles, refractive index 1.45, average particle diameter 3.4 μm, trade name “FB-3SDC”, manufactured by Denki Chemical Co., Ltd.

Glass particles: filler, refractive index 1.55, composition and composition ratio (mass %): inorganic particles of SiO ₂ /Al ₂ O ₃ /CaO/MgO=60/20/15/5, average particle diameter 20 μm

Fumed silica: Thixotropically imparted particles, average particle size 7 nm, trade name "R976S", manufactured by Evonik

Example 1

A white composition was prepared by mixing 46.6 mass % of the silicone resin composition, 3.0 mass % of titanium oxide, 48.5 mass % of glass particles, and 1.9 mass % of fumed silica. The white composition was applied on a release sheet (separator, trade name "SE-1", thickness 50 μm, manufactured by FUJICO Corporation) with a comma blade, and heated at 120° C. for 10 minutes to form a C-stage white layer. The thickness of the white layer is 100 μm.

Next, 41.4 mass % of the silicone resin composition, 40 mass % of silica particles, 18 mass % of glass particles, and 0.6 mass % of fumed silica were mixed to prepare a light-diffusing composition. The light-diffusion composition was apply|coated on the white layer with a comma blade, and the light-diffusion layer of B-stage was formed by heating at 80 degreeC for 10 minutes. The thickness of the light diffusion layer was 150 μm.

Thereby, in the state supported by the peeling sheet, the cover sheet which consists of a white layer and a light-diffusion layer is manufactured.

Examples 2 to 15

Except that the mixing ratio of titanium oxide in the white composition (ie, the white layer), the mixing ratio of the silica particles in the light-diffusing composition (ie, the light-diffusing layer), and the thicknesses of the white layer and the light-diffusing layer were changed to those described in Table 1. A cover sheet was produced in the same manner as in Example 1, except for the mixing ratio and thickness of .

Comparative Example 1

In the white composition, a cover sheet was produced in the same manner as in Example 1, except that titanium oxide was not blended. That is, the cover sheet of Comparative Example 1 was formed of a non-white layer (transparent layer) and a light-diffusion layer.

Comparative Example 2

A cover sheet was produced in the same manner as in Example 1, except that silica particles were not incorporated into the light-diffusing composition. That is, the cover sheet of Comparative Example 2 was formed of a white layer and a non-light diffusing layer (transparent layer).

Example 16

Except changing the mixing ratio of the silica particles in the light-diffusing layer and the thickness of the white layer to the mixing ratio or thickness described in Table 1, and changing the heating conditions of the light-diffusing composition to 80° C. for 20 minutes, the same The cover sheet was produced in the same manner as in Example 1.

(Measurement of thickness)

The thicknesses of the light-diffusion layer and the white layer were measured with a measuring instrument (optical ruler, manufactured by Citizen).

(Measurement of brightness)

The brightness of the cover sheets of each example and each comparative example was measured by using an ultraviolet-visible-near-infrared spectrometer and by the transmittance measurement method of an integrating sphere.

Specifically, under the conditions of 90° C., 0.1 MPa, and 10 minutes, the cover sheets obtained in each Example and each Comparative Example were thermocompressed to the glass slide so that the light-diffusion layer was in contact with the glass slide. . Next, the peeling sheet was peeled off, and the light-diffusion layer was C-staged by heating at 150° C. for 120 minutes. At this time, a sample for luminance measurement (a laminate of glass slide/light diffusion layer/white layer) was obtained.

Next, only a glass slide was set on an ultraviolet-visible-near-infrared spectrometer (“V-670”, manufactured by JASCO Corporation), and light having a wavelength of 380 to 780 nm was irradiated to perform standard measurement. After that, the sample was set, the same light as above was irradiated, and the transmission spectrum of the sample was measured. Based on the transmission spectrum, it was calculated based on JIS Z 8781-4:2013, and the luminance L* of the cover sheet was calculated. Table 1 shows the results.

Moreover, the light-diffusion layer of B-stage before C-staging was measured similarly, and the same result as the light-diffusion layer of C-stage was obtained.

(Measurement of half-value angle of light-diffusion layer)

By arranging the light-diffusion layer 3 produced by each Example and each comparative example on the glass slide 70, the sample 71 for half-value angle measurement was produced.

Next, a spectrophotometer (GC5000, manufactured by Nippon Denshoku Kogyo Co., Ltd.) was prepared, the light source 72 was fixed on the upper side of the sample 71 with a gap (5 cm), and the light source 72 was arranged on the lower side of the sample 71 with a gap (3 cm). Detector 73 (refer to FIG. 6 ).

Next, the sample 71 is irradiated with incident light (C light source) from the light source 72 .

The intensity I ₀ of the front item was measured by using the transmitted light transmitted through the sample 71 and reaching directly below the light source 72 as front light at an angle of 0°. Next, the detector 73 was moved from the front (0°) to the oblique direction (-60° to 60°), and the intensity of the transmitted light in the oblique direction was measured.

The angle at which the intensity I ₀ of the front light becomes half of the intensity I _1/2 is measured, and the angle range α that emits more than half of the intensity is calculated. Table 1 shows the results.

(Measurement of dynamic viscoelasticity (shear storage modulus G') of phosphor layer)

The dynamic viscoelasticity measurement was performed on the B-stage phosphor layers obtained in Example 1 and Example 16 under the following conditions.

[condition]

Viscoelastic device: rotational rheometer (C-VOR device, manufactured by Malvern)

Specimen shape: circular plate shape

Sample size: thickness 225μm, diameter 8mm

Deformation: 10%

Frequency: 1Hz

Plate diameter: 8mm

Gap between boards: 200μm

Heating rate 20℃/min

Temperature range: 20～200℃

Fig. 7 is a graph showing the relationship between the shear storage modulus G' and the temperature T at this time.

The minimum value of the shear storage modulus G' of the light-diffusing layer of Example 1 was 25 Pa. The minimum value of the shear storage modulus G' of the light-diffusing layer of Example 16 was 1980 Pa.

(Manufacturing method A of three-layer covering element)

A plurality of optical semiconductor elements (1.1 mm square, 150 μm thick, manufactured by Epistar Corporation) were prepared with phosphor layer-covered elements having a substantially rectangular shape in plan view, the top and side surfaces of which were covered with a phosphor layer (containing a yellow phosphor). The thickness of the phosphor layer disposed on the upper surface of the optical semiconductor element was 200 μm.

Next, a temporary fixing sheet including a support plate (stainless steel carrier) and an adhesive sheet ("REVALPHA", manufactured by Nitto Denko Corporation) arranged on the upper surface of the support plate was prepared.

The electrodes on the lower surface of the optical semiconductor element were embedded in the adhesive sheet, and the phosphor layer-covered elements were arranged on the temporary fixing sheet at intervals of 1.77 mm, five in the front-rear direction, and five in the left-right direction (Fig. 2A). . Thus, the phosphor layer-covered element assembly was obtained.

Next, the phosphor layer-covered element assembly was fixed to the upper surface of the lower plate of the thermocompressor so that the phosphor layer covered the element on the upper side, and on the other hand, the light-diffusion layer was on the lower side. The cover sheets of Examples 1 to 15 or each of the comparative examples were fixed to the lower surface of the upper plate of the thermocompression bonding machine ( FIG. 2B ). Thereafter, thermocompression bonding was performed under the conditions of 90° C., 0.1 MPa, and 10 minutes. At this time, thermocompression bonding was performed so that the light-diffusion layer disposed on the upper surface of the phosphor layer-covered element was compressed by 10 μm, that is, the light-diffusion layer on the upper surface of the phosphor layer was laminated in the obtained three-layer cover element. The light diffusion layer of the front cover sheet was reduced by 10 μm ( FIG. 2C ). Specifically, when the thickness of the light-diffusion layer of the cover sheet is 150 μm, the thickness of the light-diffusion layer of the three-layer cover element after pressing is 140 μm.

Next, the peeling sheet was peeled off, and the light-diffusion layer was C-staged by heating in a 150° C. oven for 120 minutes ( FIG. 2D ).

Next, after cutting the white layer and the light-diffusion layer between the adjacent optical semiconductor elements with a dicing machine and singulation, the temporary fixing sheet is peeled off ( FIG. 2E ).

Thus, the three-layer covering element A was produced.

(Manufacturing method B of three-layer covering element)

In the same manner as described above, a phosphor layer-covered element assembly was obtained ( FIG. 4A ).

Next, as a material for forming the side portion of the light-diffusion layer, the light-diffusing composition prepared in Example 16 was used. The light-diffusing composition is filled between the phosphor layer covering elements, and the light-diffusing layer side portions are formed by heating. The upper surface of the formed light-diffusion layer side portion and the upper surface of the optical semiconductor element are on the same plane ( FIG. 4B ).

Next, the phosphor layer-covered element assembly was fixed to the upper surface of the lower plate of the thermocompressor so that the phosphor layer covered the element on the upper side, and on the other hand, the light-diffusion layer was on the lower side. The cover sheet of Example 16 was attached to the lower surface of the upper plate of the thermocompressor (FIG. 4C). Thereafter, thermocompression bonding was performed under the conditions of 90° C., 0.1 MPa, and 2 minutes ( FIG. 4D ). At this time, the light-diffusion layer arranged on the upper surface of the phosphor layer covering element is not compressed. That is, in the obtained three-layer cover element, the thickness of the light-diffusion layer on the upper surface of the phosphor layer was the same as the thickness of the light-diffusion layer of the cover sheet before lamination.

Next, the peeling sheet was peeled off, and the light-diffusion layer was C-staged by heating in an oven at 150° C. for 120 minutes ( FIG. 4E ).

Next, after the white layer, the light-diffusion layer, and the light-diffusion layer side part between adjacent optical-semiconductor elements were cut|disconnected by a dicing machine, and the temporary fixing sheet was peeled off (FIG. 4F).

Thus, the three-layer covering element B was produced.

(Measurement of color uniformity in the angular direction)

The three-layer cover elements A to B of the respective Examples and Comparative Examples were flip-chip mounted on a diode substrate to obtain an optical semiconductor device. A current of 300 mA was applied to the optical semiconductor device to cause the optical semiconductor device to emit light. At this time, the chromaticity (CIE, y) of light emitted from the frontal direction (0°: upward direction) to the oblique direction (-60° to 60°) is measured, and the chromaticity of light at 0° and the light at ±60 are obtained. The difference in chromaticity (Δu'v').

In the measurement, a multi-channel spectrometer ("MCPD-9800", manufactured by Otsuka Electronics Co., Ltd.) was used for measurement. Table 1 shows the results.

In addition, if the difference (Δu'v') is less than 0.0040, since no yellow ring is observed, it can be judged as very good. In addition, when it exceeds 0.040 and is less than 0.0050, since a yellow ring is hardly observed, it is judged to be good. If it exceeds 0.0050 and is less than 0.0060, the yellow ring is only slightly observed, so it is judged as possible. If it exceeds 0.0050, since a yellow ring is clearly observed, it is judged as impossible.

(Appearance of three-layer covering element)

The appearances of the three-layer covering elements A to B of the respective Examples and Comparative Examples were visually observed from the white layer side, and evaluated as follows. Table 1 shows the results.

⊚: The color (yellow) of the base (phosphor layer) could not be confirmed at all.

○: The color of the base could hardly be confirmed.

△: The color of the base can be slightly confirmed.

×: The color of the base can be clearly confirmed.

(Measurement of the brightness of the three-layer covering element)

The three-layer cover elements A to B of the respective Examples and Comparative Examples were flip-chip mounted on a diode substrate to obtain an optical semiconductor device. A current of 300 mA was applied to the optical semiconductor device, and the total luminous flux was measured. In addition, the measurement was performed using a multi-channel spectrometer (“MCPD-9800”, manufactured by Otsuka Electronics Co., Ltd.) under the measurement conditions of an exposure time of 19 ms and a cumulative count of 16 times. Table 1 shows the results.

[Table 1]

In addition, the above-mentioned invention has been described as an exemplary embodiment of the present invention, but it is merely an example and is not intended to be interpreted as a limitation. Modifications of the present invention that are apparent to those skilled in the art are also included in the scope of the claims of the present invention.

【Industrial Availability】

The optical semiconductor element covering sheet of the present invention can be applied to various industrial products, for example, can be used for light-emitting devices such as white optical semiconductor devices.

Claims (9)

1. An optical semiconductor element covering sheet for directly covering an upper surface and a side surface of a phosphor layer covering element comprising an optical semiconductor element and a phosphor layer covering the optical semiconductor element, which is characterized by, It has a light-transmitting white layer containing white particles and a light-diffusing layer containing light-diffusing particles in this order along the thickness direction, Wherein, the light-transmitting white layer is a thin sheet with uniform thickness extending along the plane direction and completely covering the light-diffusing layer. 2. The sheet for covering an optical semiconductor element according to claim 1, wherein The luminance L* in the thickness direction of the sheet for covering an optical semiconductor element is 51.2 or more and 67.7 or less. 3. The sheet for covering an optical semiconductor element according to claim 2, wherein The luminance L* in the thickness direction of the sheet for covering an optical semiconductor element is 55.7 or more and 66.6 or less. 4. The sheet for covering an optical semiconductor element according to claim 1, wherein The half-value angle of the light-diffusion layer is 20° or more and 120° or less. 5. The sheet for covering an optical semiconductor element according to claim 4, wherein The half-value angle of the light-diffusion layer is 40° or more and 120° or less. 6. The sheet for covering an optical semiconductor element according to claim 1, wherein The thickness of the light-transmitting white layer is 30 μm or more and 200 μm or less. 7. The sheet for covering an optical semiconductor element according to claim 1, wherein The thickness of the light-diffusion layer is 30 μm or more and 600 μm or less. 8. The sheet for covering an optical semiconductor element according to claim 1, wherein The light-diffusion layer contains a B-stage resin. 9. The sheet for covering an optical semiconductor element according to claim 8, wherein The curve representing the relationship between the shear storage modulus G' and the temperature T obtained by the dynamic viscoelasticity measurement of the light diffusing layer under the conditions of a frequency of 1 Hz and a heating rate of 20 °C/min has a minimum value, The temperature T in the minimum value is in the range of 40°C or more and 200°C or less, The shear storage modulus G' in the minimum value is in the range of 1,000 Pa or more and 90,000 Pa or less.

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